Q:

How does water boil?

A:

Quick Answer

According to Elmhurst College, the molecules in a liquid are packed closely together and make random movements, as the molecules slip past each other. As the liquid is heated, the kinetic energy increases, which causes the motion of the molecules to increase. Eventually, the motion becomes so intense that the forces of attraction between the molecules are disrupted, and the molecules break free of the liquid, becoming a gas.

Know More

Full Answer

Since the polarity of the molecules determines the forces of attraction between the molecules in their liquid state, different molecules have different boiling points. In water, molecules that are bonded by hydrogen bonding present a special case of polar dipole forces exerting a very strong effect to maintain the liquid state. When compared to similar molecules in Group VI of the periodic table, water has an abnormally high boiling point of 100 degrees Celsius. If water behaved as a normal polar molecule, it would boil at about -100 degrees Celsius.

According to Wikipedia, adding a water-soluble substance, such as salt or sugar, increases the boiling point of water. Even though adding salt, in this way at a palatable level, will barely make a noticeable difference, it is possible to notice the difference in boiling point by adding salt.

Learn more about Thermodynamics

Related Questions

  • Q:

    What forces must be overcome for a substance to melt?

    A:

    In order for a substance to melt, it must absorb enough energy to overcome the intermolecular bonds holding its molecules together. These bonds may be ionic, molecular, covalent or metallic, depending on the material involved. Ionic bonds require the most energy to overcome, while molecular bonds are easier to break.

    Full Answer >
    Filed Under:
  • Q:

    What is the difference between heat and temperature?

    A:

    Heat measures the movement of molecules in an object, while temperature measures the average energy or heat generated by the molecules in an object. The faster the molecules move, the more heat they produce and the higher their temperatures become.

    Full Answer >
    Filed Under:
  • Q:

    How does an ice cube melt?

    A:

    Ice cubes melt as the molecules of air, water or other substances around the ice transfer heat into the molecules of the ice itself. As the temperature increases, the bonds change inside the ice, entering a liquid phase and turning into water, according to About.com.

    Full Answer >
    Filed Under:
  • Q:

    Why does heat rise?

    A:

    Hot air rises because when a substance is hot, its molecules are farther apart, which makes the hot air less dense and, therefore, lighter than cooler air. Air is generally warmer nearer the surface of the Earth because of the sun's radiating heat. When hot air rises, it starts to get cooler and eventually it sinks back down to the surface.

    Full Answer >
    Filed Under:

Explore